The Taj Mahal diamond was given to Taylor in 1972 by Richard Burton for her 40th birthday. It’s rumored that the diamond was originally owned by the emperor Shah Jahan (1592-1666), who built the Taj Mahal in memory of his late wife, Mumtaz-i-Mahal.

In 2011, Christie’s auction house sold the piece of jewelry for $8.8 million to Daniel Peng. Just months after the purchase, however, Peng started to doubt that the diamond originally belonged to the emperor so he canceled the purchase. According to Christie’s, he’s an “important customer,” so the auction house gave him back his money.

Christie’s is now asking that Taylor’s estate returns the money from the purchase, but the estate is refusing.

On May 11, the estate filed a complaint that said: “the conditions of sale that governed the auction, to which both Christie’s and the buyer were contractually bound, did not require Christie’s to rescind the sale.”

The auction house only described the jewel as an “Indian” diamond in the catalog without giving it an age, but according to Taylor’s estate, Christie’s “went beyond the language of the catalogue” when describing the diamond in public appearances before the auction and mentioned the where the jewel came from.

The estate claimed in the complaint that the “binding nature of the conditions of sale” never changed, therefore the auction house had no right to approve the return.

“The Trust has declined to refund the money to Christie’s on the ground that Christie’s cancellation of the sale was objectively unreasonable and, therefore, unwarranted under the terms of the Consignment Agreement.”

Now, the auction house is holding the funds from the sale of a Bulgari ring, worth $2,900,000, until the estate gives back the money from the Taj Mahal diamond.